Kate Upton trains with the US Marines

American model Kate Upton has been working out with the US Marines.

The 25-year-old model was put through her paces by the Marines in Detroit as she helped to promote the upcoming Marine Week celebration in the US city.

The improbable fitness session saw the blonde beauty don military attire as she successfully completed a series of aerobic exercises, with her fiance, Detroit Tigers baseball star Justin Verlander, watching on from the sidelines.

Other Tigers players' wives and girlfriends also took part in the workout, which was staged at Wayne State University's athletic complex.

But Kate was the most high-profile figure to lend her support to the cause, which is designed to ensure the US public develops a better understanding of the Marine's work.

And the blonde beauty subsequently tweeted: "Thanks to the @USMC and GySgt Sara Pacheco for getting me ready for #MarineWeek (sic)"

Meanwhile, Kate recently admitted she won't be going on diet before her wedding.

The American model is busy planning her big day, but has insisted said she won't be getting "on a scale" beforehand because she doesn't care how much she weighs.

She explained: "I never get on a scale because you can't judge yourself for how much you weigh. What really matters is how good I feel."

Despite this, Kate has been hard at work with her personal trainer Ben Bruno, who helps with her fitness regime.

Of her partnership with Ben, the model previously said: "Ben is an amazing trainer. He really keeps you moving forward and staying competitive with yourself to try to have the best workout that you personally have ever had to make you feel and look your best.

"I reached a place in my career where I didn't think of my body as something that I wanted to fit into a certain size; I started looking at my body as a function to help me live my life the best I can - to have energy and to feel strong."